# The Spitzer-HETDEX Exploratory Large Area Survey II: Dark Energy Camera and Spitzer/IRAC Multiwavelength Catalog

## TL;DR

This paper presents a comprehensive multiwavelength catalog combining DECam optical data with Spitzer IRAC infrared data over a large survey area, enabling detailed extragalactic studies and redshift estimation.

## Contribution

The paper introduces new deep, wide-area multiwavelength catalogs for the SHELA survey, including validated photometry and redshift estimates, facilitating future galaxy evolution research.

## Key findings

- Catalog reaches 24.5 AB mag depth in $riz$ bands.
- Photometric redshifts recover SDSS spectroscopic redshifts with 0.04 scatter.
- IRAC flux measurements enable multiwavelength galaxy analysis.

## Abstract

We present the $ugriz$-band Dark Energy Camera (DECam) plus 3.6 and 4.5 $\mu$m IRAC catalogs for the Spitzer/HETDEX Exploratory Large-Area (SHELA) survey. SHELA covers $\sim24$ deg$^{2}$ of the Sloan Digital Sky Survey (SDSS) Stripe 82 region, with seven bandpasses spanning a wavelength range of 0.35 to 4.5 $\mu$m. SHELA falls within the footprint of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), which will provide spectroscopic redshifts for $\sim200{,}000$ Ly$\alpha$ emitters at $1.9<z<3.5$ and also for $\sim200{,}000$ [OII] emitters at $z<0.5$. SHELA's deep, wide-area multiwavelength images combined with HETDEX's spectroscopic information, will facilitate many extragalactic studies, including measuring the evolution of galaxy stellar mass, halo mass, and environment from $1.5<z<3.5$. Here we present $riz$-band selected $ugriz$-band DECam catalogs that reach a $5\sigma$ depth of $\sim24.5$ AB mag (for point sources with an aperture that encloses $70\%$ of the total flux) and cover $17.5$ deg$^{2}$ of the overall SHELA field. We validate our DECam catalog by comparison to the DECam Legacy Survey (DECaLS) DR5 and the Dark Energy Survey (DES) DR1. We perform IRAC forced photometry with The Tractor image modeling code to measure 3.6 and 4.5 $\mu$m fluxes for all objects within our DECam catalog. We demonstrate the utility of our catalog by computing galaxy number counts and estimating photometric redshifts. Our photometric redshifts recover the available $\left\langle z \right\rangle = 0.33 $ SDSS spectroscopic redshifts with a $1\sigma$ scatter in $\Delta z/(1 +z)$ of 0.04.